1. Field of the Invention
The present invention relates to a device for grasping and transporting objects, comprising at least one supple element for grasping an object. This supple element is inflatable with a pressurized fluid and in its inflated state it acts on the object by tightening on it. The object of the invention is also to provide a method for finishing friable objects using the device.
2. Description of the Prior Art
When several sand cores with simple shapes are simultaneously removed from a core case, it is possible to advantageously position the core ejector and to introduce a fork below all the cores making it possible to support and remove the group of cores from the case.
On the other hand when the cores have complicated shapes and/or are oriented at different angles, it is impossible to return the group of cores to the case with a single fork.
The present invention has as its object a device for grasping and transporting objects which makes it possible to simultaneously grasp several objects with the same complicated shape and/or oriented at different angles.
The invention also has as its object a method for finishing friable objects using such a device for grasping and transporting, and which, in particular, makes it possible to trim foundry sand cores to eliminate flash caused by the joint surface of the core case so as to prevent fissuring in objects cast with these cores, such as automobile suspension arms.
The device in conformance with the invention for grasping and transporting objects comprises at least one pair of inflatable, supple pads mounted opposite each other on a common support which is movable relative to the object being grasped. When these pads are moved in the direction of each other in such a manner as to leave between them, in the non-inflated state, a space slightly greater than the distance separating two opposing surfaces of the object or a relief portion of the object, they clamp said surfaces between themselves when inflated.
This device can be adapted without difficulty to grasp objects of any shape by means of an appropriate adaptation of the support which bears the inflatable pads.
In regard to this matter it should be noted that the inflatable pads used in pairs to clamp objects or parts of different objects between them differ both from the point of view of function and structure from known inflatable fingers for grasping objects which are lowered and inflated in a recess in the object. Those inflatable fingers also have the inconvenience of being very fragile.
Each inflatable pad of the device according to the invention is made up of a body revolution made of flexible material, for example rubber or plastic, in the shape of a cup with a cylindrical exterior lateral surface, having an exterior annular rim opposite the base of the cup. This pad is connected to the support by a mounting exhibiting, on the attachment surface with the support, a tip whose exterior shape corresponds to the interior shape of the pad. This tip is encircled at its base by an groove with a depth slightly less than the thickness of said rim of the pad. The mounting includes a pressurized fluid supply opening at the free extremity of the tip, facing the base of the pad attached to said tip.
The pad, is thus simply attached to the tip of the mounting and when the mounting is thus fitted to the support, the rim of the pad is clamped between the mounting and the support. In case of damage to one pad, only the corresponding mounting need be detached to change the pad.
Preferably the support exhibits, at the point of attachment of each pad mounting, a passage orifice whose diameter corresponds to the exterior diameter of the body of the cup-shaped pad and whose depth is equal or slightly greater than the axial distance between the attachment surface of the mounting and the exterior surface of the base of the pad. Thus, when the pad is uninflated, its base does not project beyond the support and does not risk being damaged by the object being grasped when the support together with the pads is placed on the object.
To increase the hold of the pad on the mounting, it is advantageous if the tip of the mounting has a shape of a truncated cone which tapers in the direction of its open end and whose cup-shaped pad body has an interior truncated cone shape flared toward the base.
In order to be able to simultaneously grasp several objects with the aid of the device, the latter comprises several supports capable of being attached in an adjustable manner to a single movable support-bearing plate.
In order to finish friable objects, particularly for fettling foundry sand cores so as to remove flash formed by the joint surface in the core case, one advantageously grasps the cores in the core case at the inside of the exterior contour of the cores and/or above the flash caused by the surface of the joint in the case with the aid of a device comprising as many inflatable padded supports as the case contains cores. Next, the cores suspended from the grasping device are brought above an assembly of thin trimming plates whose interior contour corresponds to the exterior contour of the cores and whose arrangement is identical to that of the cores in the case. The cores are then lowered so that they penetrate into the plates to a depth such that the flash formed by the surface of the joint of the case is removed by the plates.